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Comp settings are 24, export is 23.98
Hi, I have a compositor who has been giving me 23.98fps movie exports for about a month. I just now received his After Effects Projects and see that he has been working in 24fps comps, exporting those as 23.98 QuickTime movies. This can cause jittery playback, right? Or does it not matter? Our Final Cut Pro specs are 23.98 Apple Pro Res HQ422. He was exporting at those specs out of comps that were built in After Effects using the preset, HDTV1080 24.
Thanks very much for any thoughts. -
8 Replies
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Ella
This will Decrease the Duration of the final clip and the playback speed will be a bit faster then original.
Vishesh Arora
VFX and Motion Graphics Artist
Films RajendraBlog:
https://digieffects.wordpress.comDemo Reel(3D):
https://www.youtube.com/watch?v=lHPgIJU_BR8 -
Thank you, VIshesh. I appreciate it, and am going to tell him to change his Comp settings for future.
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Actually, sorry, one more detail: if all the clips are ten seconds or less, will the 23.98 v 24fps still matter or is it only with longer clips where frames would start to be dropped?
My main concern is that pans will look jittery.
So far the duration of the clips has not been affected, the total running times are correct. -
[Ella Currer] “Hi, I have a compositor who has been giving me 23.98fps movie exports for about a month. I just now received his After Effects Projects and see that he has been working in 24fps comps, exporting those as 23.98 QuickTime movies. This can cause jittery playback, right? Or does it not matter? Our Final Cut Pro specs are 23.98 Apple Pro Res HQ422. He was exporting at those specs out of comps that were built in After Effects using the preset, HDTV1080 24.”
Presumably your source footage was also 23.976 (what FCP erroneously calls 23.98) fps.
If your artist was correctly interpreting the footage at 23.976 but working in a 24.0 comp, he’ll have one duplicated frame every thousand frames (23976-24000 = -24; 24:24000 = 1:1000)
[Vishesh Arora] “This will Decrease the Duration of the final clip and the playback speed will be a bit faster then original.”
This will not happen automatically; most applications will honor the stated frame rate and thus the durations will be the same. Instead, they will resample the movie temporally, using one of three methods: dropping or repeating frames as necessary (stuttery or jumpy), blending frames (soft), or synthesizing new frames via optical flow (blobby).
Changing the playback speed will only work if you can be sure you are dropping only the erroneously repeated frames; if you drop good frames and keep the bad repeating frames, you’re making the problem worse, not better.
[Ella Currer] “I appreciate it, and am going to tell him to change his Comp settings for future.”
If the footage you gave him was 23.976, he should change his comp settings and re-render what he’s already incorrectly supplied at 24.0, too.
If the footage you gave him was 24.0, you should be working at 24.0 and can conform the output to 23.976 at the end if necessary.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events -
Thank you for this detailed and much needed response. My footage is 23.98 so I don’t know why he went to 24, I think it was a mistake. I’m going to go back and re-render using the native comp settings because some pans are looking jittery.
Thanks so much again, this really helps!
Ella -
Walter
If suppose I have a footage at 25 fps and I import it as 23.98 fps, then also will this not decrease the duration of my output?
Vishesh Arora
VFX and Motion Graphics Artist
Films RajendraBlog:
https://digieffects.wordpress.comDemo Reel(3D):
https://www.youtube.com/watch?v=lHPgIJU_BR8 -
[Vishesh Arora] “If suppose I have a footage at 25 fps and I import it as 23.98 fps, then also will this not decrease the duration of my output?”
If you import 25 fps footage, then use Interpret Footage to change its frame rate to 23.976, then you will have all perfect frames, but your output will be longer. Imagine you have 30 seconds of 25 fps footage — that’s 750 frames. 750 frames played back at 23.976 fps is ~31.28 seconds.
If you import 25 fps footage, leave its interpretation alone, and drop it into a 23.976 fps comp, then its duration will be unchanged, but you will have to skip frames to keep time. Sticking with our previous example, 30 seconds of 23.976 fps material is 720 frames. To squeeze the 750 frames of our 30 seconds of 25 fps material into only 720 frames at 23.976, we’ll have to drop a total of 30 frames, or 1 per second.
That might make a little more sense if you drop some footage into a comp and step through it yourself.
Walter Soyka
Principal & Designer at Keen Live
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
RenderBreak Blog – What I’m thinking when my workstation’s thinking
Creative Cow Forum Host: Live & Stage Events -
Thanks Walter. I was a little bit confused between these two these things. Thanks for the explanation.
Vishesh Arora
VFX and Motion Graphics Artist
Films RajendraBlog:
https://digieffects.wordpress.comDemo Reel(3D):
https://www.youtube.com/watch?v=lHPgIJU_BR8
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